With the Big One a constant possibility and many lives potentially at risk, why hasn't more been done to alert and protect Southern Californians?

One little boy lay on his back with a leg gash so bad that bone and tissue protruded through his skin. Firefighters carried more injured students to a triage area, where one girl had blood streaming from a head wound and another had burns across her face.

The injuries at Rosemont Avenue Elementary School west of downtown Los Angeles were all fake, and part of Thursday's Great California ShakeOut earthquake preparedness drill. But the message was real: When a Big One hits Southern California, there will be casualties. So have we taken enough precautions to minimize deaths and injuries?

The short answer is no. A series of stories by my colleagues Rong-Gong Lin II, Doug Smith and Rosanna Xia has made clear that dozens of concrete buildings in Los Angeles could get flattened, but city officials have done little or nothing to respond until now. Thanks to the stories, which exposed the possibility of catastrophic loss of life, Mayor Eric Garcetti and others are now considering their options.

It's not that no precautions have been taken in Los Angeles and the rest of California. Overpasses, bridges and hospitals have been upgraded to withstand quakes, and homes and office buildings have been voluntarily reinforced. But after the 1994 Northridge quake, which cost 60 lives, a city proposal to survey vulnerable buildings and require upgrades eventually died, with former Mayor Richard Riordan expressing concerns about imposing new regulations on business owners.

And so here we are, surrounded by potentially deadly faults, with scientists warning that a Big One is a certainty. And no clear plan exists on what to do about buildings that could come crashing down, killing hundreds of people.

At the Rosemont drill, Bob Spears, former director of emergency services for Los Angeles Unified, said local schools would be among the safest places to be when an earthquake hits. Newer schools were designed to withstand significant shaking, and older schools have been retrofitted.

"But additional public health and safety can be preserved for a small amount of money," he said, referring to an early warning system that hasn't been activated because of funding issues.

"The USGS has it, but it hasn't been rolled out," said Lucy Jones, the U.S. Geological Survey scientist often called the Earthquake Lady. "We've built the airplane, but we haven't hired the crew yet or the air traffic controllers, and right now we have staff doing this on a bare-bones budget that's not at a level of reliability."

Jones, who was also at the Rosemont drill, told me a mere $11 million is all that's needed to staff and activate a system in which dozens of sensors — already in place — would detect seismic activity early enough to make a difference. Among other things, she said, trains could be stopped to avoid derailments and hospitals could protect patient safety and switch to backup power systems.

Jones said that in the event of a magnitude 7.8 earthquake on the San Andreas Fault, with an epicenter near the Salton Sea, it would take about 75 seconds for the waves to hit downtown Los Angeles. And that's long enough to make a difference.

"Unretrofitted concrete buildings of a certain design in Hollywood might fall in a San Andreas earthquake, and they would almost certainly fall down in a Hollywood earthquake," Jones said, noting that a fault runs through that part of the city. And the city's other commercial corridors would also be vulnerable.

"We estimate that to be the biggest source of mortality, of people dying, and it would be a big stress on the healthcare system and a particular hit to economic recovery," Jones said.

A building that falls is likely to damage nearby buildings, whether they're earthquake safe or not, she said. There's also the possibility of ruptured gas, electric and water lines. About 70% of the water delivery lines in California are made of brittle piping, Jones said, and they might well be ruptured in a big quake, making it difficult to fight the many fires that are likely to flare.

"San Francisco has an underground water distribution system that was put in after the 1906 earthquake," said Jones, and those cisterns were put to use fighting fires after the 1989 quake. In Los Angeles, she said, "we don't have that."

All of these issues have to be taken up by state and local public officials in Southern California, with scientists and building owners helping to come up with a plan to identify buildings at risk and remedies to upgrade them. That could involve tax incentives, a bond measure or some other way to share costs — possibly including rent increases — so that no one party carries the full burden.

That'll be tricky, expensive and fraught with legal issues, but none of that should stand in the way of making at least minimal effort to prevent loss of life.

Early last week, Garcetti sounded unacceptably soft on the matter, worried about putting too heavy a burden on building owners and saying "even if we spend $10 billion" reinforcing buildings, "there's going to be an earthquake that can take them down."

By week's end, he'd met with Jones and said he wanted an earthquake czar and promised urgent action on improving seismic safety.

At the Rosemont drill, I told Jones it was hard to believe — and more than a little crazy — that here in the heart of earthquake country, it took a series of stories in the newspaper to get people moving on such a critical matter of public safety.

Two things are certain. There will be a big earthquake, and few of us will have made even the most elementary preparations. And if lots of lives are lost, no excuses will be acceptable as to why we weren't better prepared.